1. Field of the Invention
The present invention relates generally to agricultural balers and to improved feeder mechanisms of the finger or tine type for such balers.
The conventional automatic baler has a bale case which extends fore-and-aft, that is in a direction parallel to the direction of the movement of the baler. Along one side of the bale case there is a crop inlet and mounted in the bale case is a reciprocable plunger adapted to move past the inlet to compress into bales crop material, such as hay or straw for example, fed into the bale case. Extending laterally from the inlet opening is a feed table or platform onto which hay, straw, or the like is deposited, this crop being lifted from a windrow by a pick-up mechanism. The crop so deposited is conveyed across the feed platform through the inlet opening and into the bale case by feed means. After each bale is formed, it is automatically banded and tied and then discharged onto the ground behind the baler or onto a trailing wagon.
2. Description of the Prior Art
Heretofore, various type of crop feed mechanisms have been applied with various success.
Some balers, such as shown in U.S. Pat. No. 2,450,082, employ a rotating auger to move the crop material from the pick-up mechanism to the bale case. On the other hand, there are a number of balers on the market which accomplish substantially the same result by the use of a multiplicity of pivotable feed fingers having a complex locus achieved by mechanical linkages (see for example, U.S. Pat. No. 2,885,953). Other balers, such as the one disclosed in U.S. Pat. No. 3,115,823 (Canadian Pat. No. 862,066), comprise a track extending transversely to the bale case and above the crop receiving platform. A feed carriage is operable on the track to engage the crop and convey it transversely of the platform and into the bale chamber. The feed carriage has depending feed fingers or tines which stand erect on a feed stroke and lay back on a return stroke. The carriage travels in a rectilinear direction perpendicular to the direction of reciprocation of the plunger. This feed mechanism is very satisfactory for balers with a relatively low capacity.
A high speed feed mechanism is illustrated in U.S. Pat. No. 3,724,363. In this design a feed finger supporting mechanism is secured at one end to a chain which is driven over a pair of sprockets to give said one end of the feed finger supporting mechanism an oval path of motion. The other end of the feed finger supporting mechanism is supported for reciprocal motion in a channel member or assembly by spaced apart roller assemblies. A portion of the channel member is secured to a crank arm which imparts to said portion of the channel member a circular motion. When conveying crop material towards the bale case, the feed fingers move relatively close to the crop receiving platform on which the crop material is deposited from the pick-up. On the return stroke, the tines are relatively more vertically spaced from this platform.
As already stated, all the foregoing feed mechanisms perform generally satisfactory. However, the requirements and demands of farmers and independent operators are increasing with the need for better and more economical baling of crops. Many of the known feeder mechanisms have a rather small capacity which in the present day environment is considered insufficient. This is particularly true for the aforementioned auger type feed mechanism and that comprising a reciprocating feed carriage with depending feed fingers or tines. Also the feed mechanisms with a multiplicity of pivotable feeder tines have a relatively small capacity.
By employing the principle of the chain driven feed mechanism of the type discussed above and disclosed in U.S. Pat. No. 3,724,363, it has been possible materially to increase the speed of a tine or finger type feed mechanism. Such a feed mechanism may operate at up to 100 strokes per minute with an improved entry of the feed tines into the crop on the feed platform and clearance of the crop from that platform.
Nevertheless, some shortcomings have been experienced. It should be noted here that the platform is surrounded by a housing which is open at the front to permit free admission of crop material from the pick-up mechanism. This housing forms a feed chamber. When a baler of this type is operated at or near its capacity, crop material accumulates at the entrance of the feed chamber when the feeder mechanism is on a working stroke and is returning outside the chamber, or at least spaced at a greater distance from the feed platform than on the working stroke, such accumulated material eventually moving into the feed chamber. However, this movement tends to be hesitant because the crop material becomes compacted whilst accumulating, and because of the restricted opening in the front of the feed chamber. The accumulation of material at the feed chamber opening is caused by the uniform or continuous supply of crop material from the pick-up and the non-uniform movement of such material from the feed chamber into the bale case.
To cure this problem, the feed mechanism should be operated at an even greater speed so as to allow less crop material to accumulate at the entrance of the feed chamber during the working and return strokes. However, this is difficult to achieve with known feed mechanisms because an increased operating speed would result in unacceptable vibrations with all the attendant problems. Furthermore, a very aggressive and positive grasp of the feed fingers or tines on the crop material is required during the entire working stroke and over the greatest possible width in the feeder chamber. Many of the known feed mechanisms fail to accomplish this as the tines only fully penetrate the crop material at a substantial distance inwardly of the end of the feed chamber remote from the bale case and as the tines retract prematurely during the working stroke. On the other hand, the feed tines should be fully retracted from the feed chamber during the return stroke so as not to interfere with the entrance of new crop in the feed chamber. This is also not always accomplished and in an attempt to solve this problem, feed tines have been pivotally mounted on the tine carrying member in a manner so as to lay back during the return stroke but these tines may cause crop material to move in a direction in the feed chamber opposite to the intended direction. This is particularly so with the feed mechanisms of the type comprising a reciprocating feed carriage as disclosed in the U.S. Pat. No. 3,115,823 (Can. Pat. No. 862,066).
Furthermore, all the crop material which has entered the feed chamber should be delivered to the bale case as soon as possible so as to allow further crop material to enter the feed chamber. Many known feed mechanisms require more than two strokes to accomplish this. This is unacceptable for present day, high capacity balers.
Many known feed mechanisms have a complicated design with many reciprocating and/or oscillating components causing high vibrations and peak loads during operation. These vibrations and peak load either become harmful and unacceptable, or substantially limit the operating speed. High vibrations caused by the feed mechanism may hamper the operation of other components of the baler. Also, these vibrations and peak loads often result in premature wear, especially when chain transmissions are used in the feed mechanism.
Also certain feed mechanisms have an excessive height which necessarily increases the overall height of the machine. A low profile machine is preferred for several reasons, the major reason being that of permitting the operator to view the discharge end of the bale case from the tractor seat.
Bale shape is another problem which is very much related to the feed mechanism. Bales of even density and of regular rectangular shape are most important for the further mechanical handling of the bale. Furthermore, disformed bales and bales of irregular shape and density in general tend to disintegrate during further handling. It has been found that with certain feed mechanisms the bale shape and density produced is inconsistent due to variations in the type of crop, the moisture content, and size, for example.
Pool bale shape is also obtained with feed mechanisms which do not deliver the crop material far enough into the bale case. In balers having such feed mechanisms, large quantities of material are deposited at the transition between the feed chamber and the bale case. When the plunger moves on a working stroke, it travels rearwardly and past the feed opening. A knife carried on the plunger and cooperable with a fixed knife adjacent the rear vertical edge of the feed opening, shears the crop material to form a wad which is rammed rearwardly and compressed. In those situations where much crop material is cut during each working stroke, a so-called "shingling" or "saw-tooth" effect, is obtained. This results in the bale having a very irregular side edge at the side where the successive wads of crop material are cut. This also means that the cutting forces are extremely high and it may happen that a safety device, such as a shear bolt in the drive line, becomes operative.